首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1447篇
  免费   45篇
  国内免费   10篇
耳鼻咽喉   6篇
儿科学   20篇
妇产科学   3篇
基础医学   152篇
口腔科学   4篇
临床医学   84篇
内科学   366篇
皮肤病学   37篇
神经病学   136篇
特种医学   81篇
外科学   266篇
综合类   1篇
预防医学   25篇
眼科学   4篇
药学   118篇
中国医学   5篇
肿瘤学   194篇
  2023年   9篇
  2022年   23篇
  2021年   58篇
  2020年   21篇
  2019年   24篇
  2018年   34篇
  2017年   27篇
  2016年   31篇
  2015年   22篇
  2014年   30篇
  2013年   48篇
  2012年   87篇
  2011年   97篇
  2010年   44篇
  2009年   42篇
  2008年   63篇
  2007年   51篇
  2006年   71篇
  2005年   61篇
  2004年   60篇
  2003年   68篇
  2002年   69篇
  2001年   48篇
  2000年   41篇
  1999年   40篇
  1998年   17篇
  1997年   13篇
  1996年   19篇
  1995年   16篇
  1994年   14篇
  1993年   7篇
  1992年   18篇
  1991年   18篇
  1990年   20篇
  1989年   17篇
  1988年   25篇
  1987年   19篇
  1986年   17篇
  1985年   17篇
  1984年   9篇
  1983年   9篇
  1982年   6篇
  1981年   8篇
  1980年   10篇
  1979年   5篇
  1978年   6篇
  1977年   6篇
  1975年   7篇
  1973年   9篇
  1971年   5篇
排序方式: 共有1502条查询结果,搜索用时 15 毫秒
1.

Objective

This study assessed the association between the timing of first epinephrine administration (EA) and the neurological outcomes following out-of-hospital cardiac arrests (OHCAs) with both initial shockable and non-shockable rhythms.

Methods

This was a post-hoc analysis of a multicenter prospective cohort study (SOS-KANTO 2012), which registered OHCA patients in the Kanto region of Japan from January 2012 to March 2013. We included consecutive adult OHCA patients who received epinephrine. The primary result included 1-month favorable neurological outcomes defined as cerebral performance category (CPC) 1 or 2. Secondary results included 1-month survival and return of spontaneous circulation (ROSC) after arrival at the hospital. Multivariable logistic regression analysis determined the association between delay per minute of the time from call to first EA in both pre- or in-hospital settings and outcomes.

Results

Of the 16,452 patients, 9344 were eligible for our analyses. In univariable analysis, the delay in EA was associated with decreased favorable neurological outcomes only when the initial rhythm was a non-shockable rhythm. In multivariable analyses, delay in EA was associated with decreased ROSC (adjusted odds ratio [OR] for one minute delay, 0.97; 95% confidence interval [CI], 0.96–0.98) and 1-month survival (adjusted OR, 0.95; 95% CI, 0.92–0.97) when the initial rhythm was a non-shockable rhythm, whereas during a shockable rhythm, delay in EA was not associated with decreased ROSC and 1-month survival.

Conclusions

While assessing the effectiveness of epinephrine for OHCA, we should consider the time-limited effects of epinephrine. Additionally, consideration of early EA based on the pathophysiology is needed.  相似文献   
2.
We investigated the presence of anti-human T-lymphotropic virus type I (HTLV-I) IgM in sera and cerebrospinal fluid from patients with HTLV-I-associated myelopathy (HAM) by Western blot analysis. Analyses of 36 serum samples revealed that most patients (31/36; 86.1%) had anti-HTLV-I IgM, whereas only four of 23 (17.4%) HTLV-I carriers had it. In studies of cerebrospinal fluid, anti-HTLV-I IgM was detected in 24 of 36 (66.7%) HAM patients, whereas none was detected in nine HTLV-I carriers. The differences were statistically significant (p less than 0.01). These results suggest that persistent active replication of HTLV-I occurs in the central nervous system as well as in the peripheral blood of HAM patients, and may contribute to the development of HAM.  相似文献   
3.
Skin tumors were produced on the back of hairless mice, HOS (HR/De), by exposure to ultraviolet B light (UVB, 290–320 nm) with 4 different protocols. The first tumors appeared earlier (in 10 weeks in group I and 7 weeks in group III) when initial intense exposure was given, followed by repeated lower-level exposures, than when the mice were exposed to the repeated UV only (in 16 weeks both in group II and group IV). All mice developed skin tumors earlier in the groups given the repeated UV exposures three times a week than in the groups given the exposures twice a week. Most of the skin tumors produced by the UVB exposure were histologically malignant, being transplantable to nude mice, and the cultured cells grown from the tumors were capable of producing tumors when injected into nude mice. The accelerated development of skin tumors by initial intense exposure and short intervals of repeated exposure observed in this study may have implications for humans who expose themselves to intense sunbathing and UV tanning (burning) by fluorescent sun lamps.  相似文献   
4.
The size of a thoracic aortic aneurysm (TAA) is an important factor of the operative indication. We experienced a ruptured TAA the diameter of which was only 4 cm. A 71 years old man was admitted due to the severe back pain under the shocked condition. We diagnosed him a ruptured TAA by CT scan. Because he had no progressive anemia and the hemodynamics was very stable, we followed him conservatively. Two months later, the operation was performed. We resected the aneurysm and inserted an aortic prosthetic graft. From the operative findings, the aneurysm was certified as a true aneurysm, and the maximal diameter was only 4 cm. First choice for the treatment of ruptured TAA is the emergent operation. But when the hemodynamics is extremely stable and the anemia does not progress at all, a conservative therapy can be selected. Even if the aneurysm is very small, the control of hypertension is quite important.  相似文献   
5.
We investigated the effect of the lgG from patients with myasthenia gravis (MG) on the degradation of normal rat junctional acetylcholine receptor (AChR) labeled with 125l-α-bungarotoxin (BuTx) and calculated the degradation rate (DR). The DR for the lgG from these patients was significantly higher than that from healthy volunteers and patients with other autoimmune diseases. For MG, DR was significantly correlated with the severity of the disease but not with anti-AChR antibody titer. DR was accelerated by lgG from patients with generalized MG whose antibody titers were in the normal range and by lgG from patients with ocular MG. These results indicate that measurement of the DR of junctional AChR in normal rats is more closely correlated with the severity of the disease than is measurement of anti-AChR antibody and that the former is a sensitive and confirmatory method for evaluating MG. © 1993 John Wiley & Sons, Inc.  相似文献   
6.
Ligation of the chemokine receptor CCR2 on monocytes and macrophages with its ligand CCL2 results in activation of the cascade consisting of phosphatidylinositol-3-OH kinase (PI(3)K), the small G protein Rac and lamellipodium protrusion. We show here that a unique clathrin heavy-chain repeat homology protein, FROUNT, directly bound activated CCR2 and formed clusters at the cell front during chemotaxis. Overexpression of FROUNT amplified the chemokine-elicited PI(3)K-Rac-lamellipodium protrusion cascade and subsequent chemotaxis. Blocking FROUNT function by using a truncated mutant or antisense strategy substantially diminished signaling via CCR2. In a mouse peritonitis model, suppression of endogenous FROUNT markedly prevented macrophage infiltration. Thus, FROUNT links activated CCR2 to the PI(3)K-Rac-lamellipodium protrusion cascade and could be a therapeutic target in chronic inflammatory immune diseases associated with macrophage infiltration.  相似文献   
7.
8.
Background: We have previously isolated a series of temperature-sensitive mutants for cell-proliferation from the BHK21 cell line, derived from the golden hamster. These mutants proliferate at 33.5 °C, the permissive temperature, but not at 39.5 °C the restrictive temperature. Using DNA-mediated gene transfer, human genes complementing these ts mutants were cloned.
Results: At 39.5 °C the tsBN250 cell line, a temperature-sensitive mutant of the BHK21 cell line, had a defect in the G1 phase, but not in the S phase. The human gene complementing tsBN250 cells was found to encode histidyl-tRNA synthetase. Indeed, the tsBN250 cell line had a single base change—guanine to adenine at the second position of the 362nd codon of hamster histidyl-tRNA-synthetase, converting arginine to histidine. Following release from serum starvation, cyclin E, but not cyclin D1, was accumulated, while, at 39.5 °C, the mRNA of cyclin D1 was normally expressed in tsBN250 cells. A similar inhibition of cyclin D1 accumulation was observed in another ts mutant, tsBN269, which has a single point mutation in lysyl-tRNA synthetase. Overexpression of cyclin D1 enabled tsBN250 cells to enter the S phase.
Conclusion: tsBN250 cells have a single point mutation in histidyl tRNA synthetase that causes a loss of histidyl-tRNA synthetase activity which in turn reduces the content of cyclin D1, but not of cyclin E, thereby resulting in G1 arrest.  相似文献   
9.
In the regulation of host defense responses such as inflammation and immunity, the secretory proteins, including membrane proteins, play central roles. Although many secretory proteins have been identified by using methods such as differential display, random screening, or the signal sequence trap method, each method suffers from poor reproducibility, low sensitivity, or time-consuming or laborious work. Therefore, the strategy for facilitating the selection of the genes encoding the secretory proteins is desired. In this paper, we describe a system for isolating the genes encoding secretory proteins by analyzing mRNAs with microsomal fractionation on serial analysis of gene expression (SAGE)-based DNA microarray system. This system succeeded in discriminating the genes encoding secretory proteins from ones encoding nonsecretory proteins with 80% accuracy. We applied this system to human T lymphocytes. As a result, we were able to identify the genes that are not only encoding secretory proteins but also expressing selectively in a specific subset of T lymphocytes. The SAGE-based DNA microarray system is a promising system to identify the genes encoding specific secretory proteins.  相似文献   
10.
The purpose of the present study was to investigate the effects of informational and motivational level of feedback stimuli on the stimulus-preceding negativity (SPN). In the time estimation task, in which a visual stimulus was presented 3 s after a voluntary movement, (a) the information level (high information and low information) and (b) the motivation level (reward and no-reward) for feedback stimuli were manipulated. Under the high-information condition, subjects received feedback information about (1) correctness (correct or incorrect), (2) direction of error (under- or overestimate), and (3) degree of accuracy (accurate or less accurate) of their time estimation. In the low-information condition, however, they received information about the correctness only. In the reward condition, they received a monetary reward for accurate time estimations but received nothing in the no-reward condition. The results demonstrated a significant interaction of information by motivation level, showing that the SPN amplitude under the reward/high-information was larger than that in the no-reward/high-information condition. The results are discussed in terms of emotional anticipation, taking into consideration the result of self-report that subjects felt to be more motivated when they received precise information.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号